Richard Preston’s “The Mountains of Pi”

The Chudnovsky brothers’ homemade supercomputer set a world record for the calculation of pi.

Photograph by Manuel Litran / Paris Match via Getty

In a 1992 piece called “The Mountains of Pi,” Richard Preston profiled two math geniuses named Gregory and David Chudnovsky. The Chudnovsky brothers had built their own supercomputer in their Upper West Side apartment and were using it to explore the inner infinity of pi. (They didn’t mention the computer—or its power requirements—to their super.) They built the computer using mail-order parts, largely at their own expense, but they were no amateurs: their homemade supercomputer rivalled factory-made ones, and they used it to set a world record for the calculation of pi. Here is Preston describing the brothers’ motivations:

Pi is by no means the only unexplored number in the Chudnovskys’ inventory, but it is one that interests them very much. They wonder whether the digits contain a hidden rule, an as yet unseen architecture, close to the mind of God. A subtle and fantastic order may appear in the digits of pi way out there somewhere; no one knows. No one has ever proved, for example, that pi does not turn into nothing but nines and zeros, spattered to infinity in some peculiar arrangement. If we were to explore the digits of pi far enough, they might resolve into a breathtaking numerical pattern, as knotty as “The Book of Kells,” and it might mean something. It might be a small but interesting message from God, hidden in the crypt of the circle, awaiting notice by a mathematician. On the other hand, the digits of pi may ramble forever in a hideous cacophony, which is a kind of absolute perfection to a mathematician like Gregory Chudnovsky. Pi looks “monstrous” to him. “We know absolutely nothing about pi,” he declared from his bed. “What the hell does it mean? The definition of pi is really very simple—it’s just the ratio of the circumference to the diameter—but the complexity of the sequence it spits out in digits is really unbelievable. We have a sequence of digits that looks like gibberish.”
“Maybe in the eyes of God pi looks perfect,” David said, standing in a corner of the room, his head and shoulders visible above towers of paper.

For a long time, the brothers used university-owned supercomputers to work on their calculation, but they had to pay exorbitantly to rent computer time. Eventually, Preston writes, “the brothers concluded that it would be cheaper and more convenient to build a supercomputer in Gregory’s apartment.” The piece’s title, “The Mountains of Pi,” refers to a visualization of pi generated by another supercomputer, programmed by David Chudnovsky over the Internet—a “piscape,” as he put it:

The photograph showed a mountain range in cyberspace: bony peaks and ridges cut by valleys. The mountains and valleys were splashed with colors—yellow, green, orange, violet, and blue. It was the first eight million digits of pi, mapped as a fractal landscape by an I.B.M. GF-11 supercomputer at Yorktown Heights, which Gregory had programmed from his bed. Apart from its vivid colors, pi looks like the Himalayas.
Gregory thought that the mountains of pi seemed to contain structure. “I see something systematic in this landscape, but it may be just an attempt by the brain to translate some random visual pattern into order,” he said. As he gazed into the nature beyond nature, he wondered if he stood close to a revelation about the circle and its diameter. “Any very high hill in this picture, or any flat plateau, or deep valley, would be a sign of something in pi,” he said. “There are slight variations from randomness in this landscape. There are fewer peaks and valleys than you would expect if pi were truly random, and the peaks and valleys tend to stay high or low a little longer than you’d expect.” In a manner of speaking, the mountains of pi looked to him as if they’d been molded by the hand of the Nameless One, Deus absconditus (the hidden God), but he couldn’t really express in words what he thought he saw and, to his great frustration, he couldn’t express it in the language of mathematics, either.
“Exploring pi is like exploring the universe,” David remarked.

“The Mountain of Pi” is available to New Yorker subscribers in our online archive. So is a second article by Preston about the Chudnovskys, “Capturing the Unicorn,” about how the brothers helped the Metropolitan Museum of Art make a perfect photograph of a famous series of tapestries known as “The Hunt of the Unicorn.”

Joshua Rothman is The New Yorker’s archive editor. He is also a frequent contributor to newyorker.com, where he writes about books and ideas.